Samotherium major Bohlin, 1926

Rios, M, Danowitz, M & Solounias, N, 2016, First comprehensive morphological analysis on the metapodials of Giraffidae, Palaeontologia Electronica 410 (10453), pp. 1-39 : 8

Samotherium major Bohlin, 1926

Specimens. AMNH 20595, NHMBe 711, AMNH 22970

Description. The medial and lateral epicondyles are similar in size and asymmetrical in morphology ( Figure 11 ). The lateral epicondyle is triangular shaped and fuller, and the distal aspect continues onto the lateral ridge. The proximal articular surface extends slightly onto the palmar surface of the lateral epicondyle. There is a small circular knob close to the median plane. An obliquely oriented groove separates the lateral epicondyle into a laterally flaring head that connects distally to the lateral ridge and a longitudinally oriented head ( Figure 4 ). There is a narrow, deep, obliquely oriented groove on the lateral aspect of the lateral epicondyle, which appears to continue down the lateral aspect of the proximal shaft. The medial epicondyle is circle-sector shaped and flatter, and it is separated from the medial ridge ( Figure 12.1 ). There is a wide and shallow groove on the medial aspect of the medial epicondyle, which ends distally in the central trough. There is a deep, narrow groove that separates the medial and lateral epicondyles and continues onto the central trough. The medial ridge is sharper and it flattens towards the distal shaft, whereas the lateral ridge is rounder, and it also flattens towards the distal shaft. There is an elongated oval fossa on the lateral aspect of the lateral ridge. The central trough is intermediate-deep in depth proximally, and becomes progressively shallower and is flat distally ( Figure 6.4 ). The pyramidal rise present, most noticeably on the proximal shaft. The lateral aspect of the lateral distal condyle flares strongly and terminates at a distinct pointed bulge, whereas the medial aspect of the medial distal condyle is more vertical. The keels of the distal condyles extend onto the distal shaft, and they likely extend outside the synovial cavity.

Figures

FIGURE 4. Three selected metacarpal characteristics. This simplified table can be used to facilitate specimen identifications and differentiate between different giraffid taxa.

FIGURE 6. Representative cross sections of right metacarpals. 1, Helladotherium duvernoyi, late Miocene, Pikermi, MNHNP 1527; 2, Birgerbohlinia schaubi, late Miocene, Samos, AMNH 20610 (reversed); 3, Okapia johnstoni, AMNH 15218 (reversed); 4, Samotherium major, late Miocene, Samos, AMNH 22790; 5, Bohlinia attica, late Miocene, Pikermi, PA 1474-1991; 6, Giraffa camelopardalis, AMNH 70016. Scale bar equals 80 mm.

FIGURE 11. Samotherium major from Samos. 1, Right metacarpal NHMBe 711; 2, Right metatarsal AMNH 22967.

FIGURE 12. Palmar views of the right metacarpals (left) and plantar views of the metatarsals (right) of certain Giraffidae. 1, Samotherium major, late Miocene, Samos, NHM Be Samos 711 (metacarpal), AMNH 22967 (metatarsal) (both reversed); 2, Palaeotragus rouenii, late Miocene, Pikermi, MNHNP 1692 (metacarpal), (reversed); MNHNP 1691 (metatarsal). Scale bar equals 200 mm.